Immune System The Body’s Defenses

3 Lines of Defense 1 st Defense Barriers that trap and kill pathogens (an organism that causes disease) Skin – chemicals in oils and sweat Breathing passages – mucus & cilia Mouth – Saliva (amylase) Stomach – Acid (hydrochloric)

2 nd Defense Inflammatory response: whit blood cells (WBC) penetrate tissue and then fight the pathogens Inflammatory response: whit blood cells (WBC) penetrate tissue and then fight the pathogens Phagocyte: A WBC which engulfs and destroys pathogens by breaking Them down.

3 rd Defense Immune Response: Special WBC’s called lymphocytes are targeted specifically at that pathogen Immune Response: Special WBC’s called lymphocytes are targeted specifically at that pathogen Antigens: Molecules on cell, which our body recognizes as friend or foe Antibodies: lock onto antigens, marking the pathogen for destruction.

AIDS (Acquired immunodeficiency syndrome) A disease caused by virus attacking WBC’s in the immune system. A disease caused by virus attacking WBC’s in the immune system. Virus is spread by sexual contact, blood, and bodily fluids.

Preventing Infectious Disease Immunity: Ability to destroy pathogens before they cause disease Active Immunity: body produces antibodies in response to presence of pathogen

Vaccination: (immunization) is when antigens are purposely introduced to immune system producing active immunity Vaccine: Weakened or killed pathogens

Passive Immunity: antibodies are given to the person, not made in body Antibiotic: chemical that kills bacteria or slows their growth without harming body cells.

Non-infectious Disease Not spread from person to person Not spread from person to person Not caused by microorganisms Not caused by microorganisms *EXAMPLE: Cardiovascular Disease *EXAMPLE: Cardiovascular Disease Allergy: immune system is over sensitive to foreign substance Allergen: any substance that causes an allergy. EXAMPLE: Pollen

Asthma: respiratory passage narrows significantly Insulin: enables cells to take glucose from blood and use it for energy. Diabetes: Pancreas fails to produce enough insulin

2 Forms of Diabetes Type I: pancreas produces too little or no insulin Type I: pancreas produces too little or no insulin *Must take insulin injections Type II: pancreas produce too little insulin *Cells don’t respond to insulin *Control via proper diet, exercise, and weight control

Cancer: cells multiply uncontrollably, destroying healthy tissue. Tumors: cancerous abnormal tissue growth Carcinogens: factors in the environment which cause cancer

Cancer & the Environment Asbestos: mineral which is similar to fiberglass found in roof shingles & insulation Asbestos: mineral which is similar to fiberglass found in roof shingles & insulation *Causes lung cancer Ultraviolet Light: from the sun and tanning beds *Changes DNA structure in skin which causes skin cancer